This application relates to a bolt and washer combination that facilitates the attachment of a bracket and liner to a convergent flap and seal in a nozzle of a gas turbine engine.
A gas turbine engine typically includes a plurality of sections, which are positioned in series. A fan section moves air downstream towards a compressor section. The compressor section compresses the air and delivers it into a combustion section. In the combustion section, air and fuel are mixed and combusted. Products of combustion pass downstream over turbines, and then outwardly through a nozzle.
It is known in the prior art to vary the cross-sectional area of the nozzle by having flaps that pivot inwardly and outwardly. Typically, a plurality of circumferentially spaced flaps and seals are positioned upstream of a throat, and are called the convergent flaps and seals. Downstream of the throat are divergent flaps and seals. The convergent flaps and seals not only move to define the throat area, but they also provide a block to prevent the products of combustion from reaching a housing outboard of the flaps and seals.
In the structure for the convergent flaps and seals, a liner typically faces the products of combustion. The liner is connected by a bracket to the flap or seal. Traditionally, the bracket has been welded to the hot liner. The bracket is then bolted to the cooler flap or seal.
In the prior art, bolting the bracket to the flaps and seals has proven to be cumbersome to initially install, and has also made replacement somewhat difficult.
The threaded attachments often were secured with sheet metal tabs, or rivets. In addition, there are challenges to utilizing the threaded fasteners, in that the flaps and seals are positioned around the entire circumference of a jet engine, and it is difficult to reach the outside of those structures, and the inside, simultaneously to tighten a nut on the threaded fastener.
This is part of the reason that the bolts needed to be staked permanently. One side of the bolt or nut must be radially outwardly of the flaps and seals, while the other must be inwardly. These are relatively large components, and it is difficult to reach both sides.
In addition, it has been proposed in the prior art to have various openings, slots, etc. to facilitate the attachment of the threaded fastener. However, all of these structures have provided a potential leakage path for products of combustion to leak, which is undesirable.